diff --git a/openslides/poll/models.py b/openslides/poll/models.py
index 706d8c503..bfdb29fce 100644
--- a/openslides/poll/models.py
+++ b/openslides/poll/models.py
@@ -12,9 +12,10 @@
 
 from django.db import models
 
-from projector.api import register_slidemodel
-from projector.models import SlideMixin
-from utils.translation_ext import ugettext as _
+from openslides.projector.api import register_slidemodel
+from openslides.projector.models import SlideMixin
+from openslides.utils.translation_ext import ugettext as _ # TODO
+from openslides.utils.modelfields import MinMaxIntegerField
 
 
 class BaseOption(models.Model):
@@ -34,7 +35,7 @@ class TextOption(BaseOption):
 class Vote(models.Model):
     option = models.ForeignKey(BaseOption)
     #profile = models.ForeignKey(Profile) # TODO: we need a person+ here
-    weight = models.IntegerField(default=1, null=True)
+    weight = models.IntegerField(default=1, null=True) # Use MinMaxIntegerField
     value = models.CharField(max_length=255, null=True)
 
     def get_weight(self, raw=False):
@@ -50,7 +51,7 @@ class Vote(models.Model):
 
 
 class CountVotesCast(models.Model):
-    votescast = models.IntegerField(null=True, blank=True, verbose_name=_("Votes cast"))
+    votescast = MinMaxIntegerField(null=True, blank=True, min_value=-2, verbose_name=_("Votes cast"))
 
     def append_pollform_fields(self, fields):
         fields.append('votescast')
@@ -63,7 +64,7 @@ class CountVotesCast(models.Model):
 
 
 class CountInvalid(models.Model):
-    votesinvalid = models.IntegerField(null=True, blank=True, verbose_name=_("Votes invalid"))
+    votesinvalid = MinMaxIntegerField(null=True, blank=True, min_value=-2, verbose_name=_("Votes invalid"))
 
     def append_pollform_fields(self, fields):
         fields.append('votesinvalid')
diff --git a/openslides/utils/modelfields.py b/openslides/utils/modelfields.py
new file mode 100644
index 000000000..72f63b51d
--- /dev/null
+++ b/openslides/utils/modelfields.py
@@ -0,0 +1,23 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+"""
+    openslides.utils.modelfields
+    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+    Modelfields for OpenSlides
+
+    :copyright: 2011, 2012 by OpenSlides team, see AUTHORS.
+    :license: GNU GPL, see LICENSE for more details.
+"""
+
+from django.db import models
+
+class MinMaxIntegerField(models.IntegerField):
+    def __init__(self, min_value=None, max_value=None, *args, **kwargs):
+        self.min_value, self.max_value = min_value, max_value
+        super(MinMaxIntegerField, self).__init__(*args, **kwargs)
+
+    def formfield(self, **kwargs):
+        defaults = {'min_value': self.min_value, 'max_value' : self.max_value}
+        defaults.update(kwargs)
+        return super(MinMaxIntegerField, self).formfield(**defaults)